feat: Config and Argument configuration plus tests for these features

[hawksight]

Helps to resolve #438 as it adds helm unittest to test the new features added.

Allows:

• Passing extraArgs to the agent.
• Allows you to embed the agent config as completely custom in the chart
• Allows you to specify a completely different configmap (& key) so config is not within the chart.
• Update to v0.1.40 of agent.
• CronJobs to v1 not v1beta1

[hawksight]

Kind of a little stuck on ensuring the actual config.yaml file is templated correctly.
See this issue for context.

Got an answer and used the snapshot feature to test default configmap settings.

[hawksight]

I think this is ready for a review now. Appreciate a good set of eyes on this as I've bumped to v0.3.0 as there's a fair few changes around config options here.

[SpectralHiss]

Only 1 minor suggestion to change the override "interface" a little bit.

[hawksight]

Had a huddle with @SpectralHiss to see if we could make the chart simpler with:

  override:
    # -- Embed the agent configuration here in the chart values
    config: 
    # -- Sepcify ConfigMap details to load config from existing ConfigMap
    configmap:
      name: 
      key: 

Or even simpler with a default of:

  override: {}

However it turned out to be too difficult to make the logic cleaner in the chart.
So for now we agreed to leave how it is and improve for the next version of the chart that will be Venafi Specific

[achuchev]

This seems to be a result of a merge conflict.

[hawksight]

Oh I was including this as the result of one of the unit tests. It actually depends what you enter as the nameOverride as to whether it counts the -RELEASE-NAME part. It caught me out as if you just use helm template --set nameOverride=agent ... then you don't see the RELEASE-NAME part. I wanted to include the output so I don't forget this subtly in the future :)